Sonar systems utilized by many of the world’s navies contain ceramic materials, as they offer solutions for situations requiring high acoustic transmission properties in low frequency environments. Morgan’s products are operable at extremely low depths, and continue to work even in the most severe bathythermal conditions, where water temperature falls as water depth increases.

To produce low frequency active sonar, Morgan manufactures a range of ‘stave’ components, assembled together to create large ceramic rings and  used as underwater projector transducers. To combat size restrictions, electrodes are positioned between each ceramic segment, with the segments then poled around the circumference. This arrangement is also known as a segmented construction and allows for very large rings to be constructed, although careful control of the tolerance is necessary to obtain a well-consolidated assembly with uniform joints. 

Features:

• Ceramic stave components range from 10 to 165 mm.
• Thicknesses range from 10 to 40 mm.
• Can be manufactured to angular specifications allowing for large diameter assembled rings to be created..
• Various additional geometries are available with a choice of specially machined notch grooves for easier integration and soldering of connecting wiring and customized angle apertures to manufacture substantially larger diameter and lower frequency transducers.
• Sub-assemblies and pre-stressing of stave sub-assemblies, complete with a range of insulated flexible wire terminals, are also offered.

Suitable materials for sonar transducers include PZT400 and PZT800 series piezoelectric formulations, which are both considered as ‘hard’ materials and therefore suitable for underwater naval operations. These piezoelectric formulations ensure low dielectric and mechanical losses in the transducer for optimum acoustic output and efficiency.  Multi-element piezoelectric rings are used to  ensure that the coupling coefficient of the transducer is substantially higher than for the single monolith piece ring with radial poling. When driven to high power, the joints and ceramic are subjected to high levels of tensile stress; therefore, some level of pre-stress is necessary to lower the rate of expansion. This is achieved through a customized process of circumferentially compressing the ring, and consolidating the whole assembly in epoxy resin.

For more information visit www.morganelectroceramics.com.